1. Field of the Invention
This invention relates to an H-bridge deactivator that utilizes an H-bridge switch network to perform activation, deactivation or reactivation of an electronic article surveillance (EAS) tag and particularly to activation, deactivation or reactivation of an acoustomagnetically activated EAS tag.
2. Description of the Related Art
Acoustomagnetically activated EAS tags are typically demagnetized by a strong magnetic alternating field with a slowly decaying field strength, Conversely, acoustomagnetically activated EAS tags can only be initially activated or subsequently reactivated by magnetizing with a strong constantly positive or constantly negative magnetic field with a slowly decaying field strength.
Therefore, existing acoustomagnetic (AM) deactivators require either high voltage (110VAC—volts alternating current) or very high voltage (200-500VDC—volts direct current) in order to generate the high currents required to produce a magnetic field of sufficient magnitude to deactivate an EAS tag. The voltages required impose special safety concerns that tend to constrain the design. Furthermore, if power is interrupted or lost, the deactivator will not work for that period of time and such deactivators are not portable. The prior solutions address uninterruptible power and portability regarding a small handheld deactivator, but not for a large deactivator or a low voltage deactivator.